Annunciator device



May 3, 1960 A. A. BAKER, JR

ANNUNCIATOR DEVICE Filed May 15, 1956 FIG. 2

M R RM y N MM M 0 D A A TTOR EY United States Patent ANNUNCIATOR DEVICE Application May 15, 1956, Serial No. 584,971

I 4 (cram-12s invention relates to electromagnetic annunciators.

The object of the invention is to provide a simple and rugged annunciator device having a minimum of parts, which will-operate reliably over long periods without requirin-g adjustment or other maintenance.

The invention resides primarily in the use of a solenoid device having a stem mounted concentrically on the soft iron armature in the manner conventional in carillon strikers. Unlike the carillon striker, however, the present device is provided with a nose piece of hard iron which will retain the armaturein its operated position so that the striker rod of the device mounted, by way of example, on a panel will stick out beyond-the surface and act as an indicator. Such an indicator may be reset manually asby pushing the-protruding indicator rod or electrically as by reversing the operating current, in which case the hard iron nose piece will be characterized by high retentivity and the energizing current for resetting must be kept below the level at which the remanent flux will not be reversed, so as to act as a bistable device.

: A feature of'the invention is the combination of a solenoidhaving a hard iron core located at one end thereof pierced concentrically to accommodate ina loose sliding fit, a cylindrical plunger mounted on a movable core of soft iron: The plunger is of such a length that its end will be practicallly flush with the end of the said hard iron core but will protrude outwardly a noticeable distance after the said solenoid has been energized and the said soft'iron core has been made to cling to the said hard iron coreby virtue of the remanent flux therein. Theforcewith which the said soft iron core clings to the hard iron end core is of an order suificient to support the weight {of the soft iron core and its attached nonmagnetic plunger when the device is mounted along a vertical In one form of the device, the said hard iron core piece may be threaded so as to be conveniently mounted on a panel.

In another form of the device, the solenoid may be wound on a plastic spool of good insulating properties and a flexible conductor attached to the soft iron core whereby an electrical connection may be made to the hard iron end core upon the operation of the device.

In another form, the hard iron end core may be constructed of material having high magnetic retentivity so that after the device has been operated by the flow of current in one direction through the solenoid, it may be released and returned to normal by causing a flow of current in the other direction through said solenoid. A very small nonmagnetic stop interposed between the surfaces of the hard iron core and the soft iron armature will facilitate the release through magnetic repulsion.

Other features will appear hereinafter.

The drawings consist of a single sheet having three figures, as follows;

Fig. 1 is a drawing partly in section of the essential Patented May 3, 1960 2 elements of the device and having associated therewith a schematic circuit diagram;

Fig. 2 is a similar view; the chief difference being in the circuit diagram; and

Fig. 3 is a perspective view showing four such annunciator devices mounted on a horizontal panel.

As shown in the drawings, the device of the present invention consists of a nose piece 1 of hard iron which may be threaded for mounting on a panel 2 by the conventional nuts 3 and 4. The magnetic properties of this hard iron must be that it will maintain sufficient remanent flux to hold the soft iron .armature 5 in operated positionwhen the device is mounted vertically, as shown in Fig. 3.

An actuating coil 6 is wound on an insulating spool 7 whichmay be secured in any manner to the nose piece 1. It is shown herein as being screwed on to nose piece but, of course, may be attached in any other convenient manner.

Loosely placed within the spool 6 is a soft iron armature 5, having secured to one end thereof a rod 8 constructed of some insulating material such as a plastic. The length of the rod is such that in an unoperated position the end of the rod 8 is practically flush with the end of the nose piece 1, as indicated by devices 9 and 10 of Fig. 3. When the device has been operated so that the air gap between the nose piece 1 and the soft iron armature 5 has been closed, the rod 8 will protrude as indicated by the annunciators 11 and 12 of Fig. 3.

The rear end of the spool 7 may be provided with a flange 13 so that the armature will not be pushed out of itsnormal position and a felt Washer 14 may be placed against this flange as a shock absorbing means.

The device may be operated either by direct or alternatingcurrent. In Fig. l a source of alternating current 15 and a button 16 for applying current from this source is indicated. When this button is operated, the air gap between the nose piece 1 and the soft iron armature 5 is closed by the movement of the armature toward and into contact with the hard iron nose piece, which will be charged with sufiicient remanent flux to avoid demagnetization by the alternating field and to thereafter hold the two pieces together. If it is desired, an electrical connection may be made to the nose piece 1 by a washer 17 and a flexible lead 18 may be attached to the armature 6 to close a circuit to a pilot lamp 19.

After the annunciator has been operated, it may be reset by pressure applied to the protruding rod 8 so that an operated annunciator, such as 11 or 12, may be returned to the unoperated state as annunciator 9 or 10.

In another form, the nose piece 20 may be constructed of a magnetic material of high retentivity so that it is virtually a strong permanent magnet but with insufiicient strength to move the soft iron armature 21 from its normal position. Such a device may be made to respond to direct current energization as by an On button 22 which will set up such a field in the air gap that the core 21 will be attracted toward the permanent magnetic nose piece 20. If, however, the energization of the coil 23 is reversed, as by the Off button 24, then a force of repulsion will be set up between these two pieces and the soft iron core will be moved away from its operated position.

In order to facilitate the operation, a stop pin may be secured to the face of the soft iron armature 21 to provide a very small air gap between the armature and the nose piece in the operated position. If, in this form of the device, the electrical connection for the operation of the pilot lamp 26 is to be provided, then the stop pin 25 may be of copper or of brass to provide an electrical connection. In another form, this stop pin may be of insulating material such as a plastic.

In Fig. 3, a pilot lamp 27 is indicated which may be commonly associated with a row of these annunciator units, such as 10 and 12 and another pilot lamp 28 is indicated as associated with another row of units such as 11 and 9.

Fundamentally the annunciator provides a device which indicates by the protrusion of-a rod and which may, in a simple manner, be reset by finger pressure thereon, or which may be reset by the pushbutton application of a reversed field.

What is claimed is:

1. An electromagnetic annunciator device consistingof a cylindrical core of magnetic material having a high degree of retentivity and initially possessing a given remanent flux, said core having a bore formed axially therein, a soft iron core having a nonmagnetic rod mounted thereon and loosely threaded through the bore of said cylindrical core, a solenoid Wound about said cores and so positioned that the air gap between said cores is placed substantially at the middle of said solenoid, means to energize said solenoid in one direction to move said soft iron core to a first position in proximity to said core of 'magnetic material, said first position being a position in which said rod noticeably protrudes from said cylindrical core, said given remanent flux being sufficient to retain said soft iron core in said first position, and means to energize said solenoid in the other direction to move said soft iron core away from said permanent magnetic core the flux created by said solenoid to move said core in said other direction being ineffective to substantially diminish the remanent flux of said cylindrical core from said given value.

2. An electromagnetic annunciator device consisting of a cylindrical core of magnetic material having a high degree of retentivity and having sufficient remanent flux to hold a soft iron core against the force of gravity, said cylindrical core having an axial bore therethrough and terminating in a threaded neck for mounting on a panel, a soft iron core having a nonmagnetic rod secured thereto, said rod being loosely fitted in the said bore of said cylindrical core, said rod and soft iron core being movable to an operated position and to an unoperated position, said rod terminating at the said end of said threaded neck when said rod and soft iron core are in said unoperated position and extending beyond said neck when-placed in said operated condition, and a solenoid wound about said cores and so positioned that the air gap between said cores is within said solenoid, said cylindrical core being so positioned relative to the flux path of said solenoid at only that portion of said cylindrical core which is in immediate proximity to said gap is linked by the flux of said solenoid whereby the operation of said device through energization of said solenoid will not substantially affect the magnitude of the remanent flux of said cylindrical core.

3. An electromagnetic annunciator device consisting of a cylindrical core of magnetic material having a high degree of retentivity, a movable soft iron core having a nonmagnetic rod attached thereto and threaded through an axial bore in said cylindrical core, a solenoid wound about the air gap between said cores, said soft iron core being within said solenoid while the major part of said cylindrical core is outside of said solenoid, first means for energizing said solenoid to cause magnetic attraction between said cores and second means for energizing said solenoid to cause magnetic repulsion between said cores, the magnetization of said core of high retentivity magnetic material being sufficiently great to retain said soft iron core in an attracted position, said magnetization being substantially unaifected by the operation of said means for energizing said cores to cause magnetic repulsion.

4. An electromagnetic annunciator device comprising a cylindrical externally threaded and coaxially bored core member of magnetic material having high retentivity, a cylindrical core member of magnetic material of low retentivity and having a rod attached to one end thereof, said rod being of insulating material of a diameter slightly less than the bore of said high retentivity member and threaded therethrough, and an energizing coil wound upon a spool of insulating material, said spool being internally threaded at one end for attachment to said high retentivity member and having an internal flange at the other end for retaining said low retentivity core member within the assembly, said spool being of a length suflicient to afiord a substantial air gap between said core members when parted and said rod being substantially flush with the end of said high retentivity member when said core members are parted said high retentivity member extending a substantial distance beyond said threaded end of said spool so that a substantial portion of said high retentivity core would not be traversed by the flux of any field generated by said coil.

References Cited in the file of this patent UNITED STATES PATENTS 

